Ammonium salts of α-ketocarboxylic acids

Abstract

This invention relates to new ammonium salts of α-ketocarboxylic acids, to their use for the production of amines in situ by photochemical decomposition and to photochemically hardenable coating compositions containing these ammonium salts.

What is claimed is: 
     
       1. Ammonium salts of α-ketocarboxylic acids corresponding to the following general formula: ##STR7## wherein n represents an integer of from about 1 to 4 A and B are the same or different and represent hydrogen, an optionally branched and/or halogen- or methoxy-substituted C 1  -C 10  -alkyl radical, a C 5  -C 15  -cycloalkyl radical, a C 6  -C 15  -aryl radical which may optionally be substituted by --OH, --R, --OR, --SR, halogen, --NO 2 , --COR, --COOH, --CN, --COOR, --CONH 2 , --OR', --SR' or --COR', a C 4  -C 10  -heterocyclic radical containing oxygen, sulphur and/or nitrogen as a hetero atom or A and B together represent a 5-membered or 6-membered cycloaliphatic ring optionally containing oxygen or nitrogen as a hetero atom, and   D represents hydrogen, halogen, --OH, --COOH, --COOR, CN, --COOH, --OR, --COR, --COR', --CCl 3 , an optionally branched C 1  -C 10  -alkyl radical, a C 4  -C 15  -cycloalkyl radical, a C 6  -C 15  -aryl radical which may optionally be substituted by --OH, --R, --OR, --SR, halogen, --NO 2 , --COR, --COOH, --CN, --COOR, --CONH 2 , --OR', --SR', or --COR' or a C 4  -C 10  -heterocyclic radical containing oxygen and/or nitrogen as a hetero atom, wherein     R represents an optionally halogen-substituted alkyl group containing from about 1 to 6 carbon atoms and   R' represents an aryl group containing from about 6 to 12 carbon atoms.   
     
     
       2. The ammonium salts of claim 1, wherein n is 1 or 2. 
     
     
       3. The ammonium salts of claim 1, wherein D and A or B is hydrogen. 
     
     
       4. The ammonium salts of claim 1, wherein A or B is an aryl radical. 
     
     
       5. The ammonium salts of claim 1, wherein the amine component has a molecular weight of from about 31 to 500. 
     
     
       6. The ammonium salts of claim 1, wherein the amine component has a molecular weight of from about 100 to 300. 
     
     
       7. The ammonium salts of claim 1, wherein the amine component contains from about 1 to 3 amine nitrogen atoms. 
     
     
       8. The ammonium salts of claim 1, wherein the amine component is a tertiary amine. 
     
     
       9. A process for releasing an amine from its blocked form, characterized in that the ammonium salt of claim 1 is irradiated with light having a wavelength of from about 250 to 500 nm. 
     
     
       10. Coating compositions based on polyurethane or epoxide precursors hardening in the presence of amines, characterized in that they contain from about 0.1 to 40% by weight, based on the solids content, of the ammonium salts of claim 1. 
     
     
       11. A process for producing ammonium salts of α-ketocarboxylic acids corresponding to the following general formula: ##STR8## wherein n represents an integer of from about 1 to 4, A and B are the same or different and represent hydrogen, an optionally branched and/or halogen- or methoxy-substituted C 1  -C 10  -alkyl radical, a C 5  -C 15  -cycloalkyl radical, a C 6  -C 15  -aryl radical which may optionally be substituted by --OH, --R, --OR, --SR, halogen, --NO 2 , --COR, --COOH, --CN, COOR, --CONH 2 , --OR', --SR' or --COR', a C 4  -C 10  -heterocyclic radical containing oxygen, sulphur and/or nitrogen as a hetero atom or A and B together represent a 5-membered or 6-membered cycloaliphatic ring optionally containing oxygen or nitrogen as a hetero atom, and   D represents hydrogen, halogen, --OH, --COOH, --COOR, --CH, --COOH, --OR, --COR, --COR', --CCL 3 , an optionally branched C 1  -C 10  -alkyl radical, a C 4  -C 15  -cycloalkyl radical, a C 6  -C 15  -aryl radical which may optionally be substituted by --OH, --R, --OR, --SR, halogen, --NO 2 , --COR, --COOH, --CN, --COOR, --CONH 2 , OR', --SR', or --COR' or a C 4  -C 10  -heterocyclic radical containing oxygen and/or nitrogen as a hetero atom, wherein     R represents an optionally halogen-substituted alkyl group containing from about 1 to 6 carbon atoms and   R' represents an aryl group containing from about 6 to 12 carbon atoms comprising reacting α-ketocarboxylic acids of the formula I with an amine component having a molecular weight between about 31 to 500 at temperatures in the range of from about -20° to +50° C.     
     
     
       12. In a process for coating substrates with coating compositions based on polyurethane or epoxide precursors which harden in the presence of amines, the improvement wherein said compositions contain from about 0.1 to 40% by weight, based on the solids content, of ammonium salts of α-ketocarboxylic acids corresponding to the following general formula: ##STR9## wherein n represents an integer of from about 1 to 4, A and B are the same or different and represent hydrogen, an optionally branched and/or halogen- or methoxy-substituted C 1-C   10  -alkyl radical, a C 5  -C 15  -cycloalkyl radical a C 6  -C 15-  aryl radical which may optionally be substituted by --OH, --R, --OR, --SR, halogen, --NO 2 , --COR, --COOH, --CN, COOR, --CONH 2 , --OR', --SR' or --COR', a C 4  -C 10  -heterocyclic radical containing oxygen, sulphur and/or nitrogen as a hetero atom or A and B together represent a 5-membered or 6 membered cycloaliphatic ring optionally containing oxygen or nitrogen as a hetero atom, and   D represents hydrogen, halogen, --OH, --COOH, --COOR, --CH, --COOH, --OR, --COR, --COR', --CCl 3 , an optionally branched C 1  -C 10  -alkyl radical, a C 4  --C 15  -cycloalkyl radical, a C 6  -C 15  -aryl radical which may optionally be substituted by --OH, --R, --OR, --SR, halogen, --NO 2 , --COR, --COOH, --CN, --COOR, --CONH 2 , --OR', --SR', or --COR' or a C 4  -C 10  -heterocyclic radical containing oxygen and/or nitrogen as a hetero atom, wherein     R represents an optionally halogen-substituted alkyl group containing from about 1 to 6 carbon atoms and   R' represents an aryl group containing from about 6 to 12 carbon atoms and said composition is irradiated with light having a wavelength of from about 250 to 500 nm.